Roger Federer emerged unscathed from a testing second set to see off Federico Delbonis 6-3 7-6 (8-6) in the opening match of his Indian Wells Masters title defence on the ATP Tour.

The world number one had looked well on his way to a comfortable second-round victory when rain halted play on Saturday with the second set tied at 2-2, but he did not have it all his own way a day later.

It was a determined Delbonis who looked to have been eased by the clearer conditions and he forced Federer to rescue a break point in the second game after the restart.

The defending champion came through, though, reaching a tie-break before his class told and it became apparent that the weather had only delayed the inevitable.

Federer charged into a 4-1 lead, then went ahead 5-2, stuttering before clinching the match with a stretching trademark volley that Delbonis returned into the net.

With Novak Djokovic dumped out an hour earlier, Federer has a golden opportunity to go on and take an outright record sixth title in California, with Filip Krajinovic up next.